§ 1131. Driving on shoulders and slopes. Except for bicycles and those classes of vehicles required to travel on shoulders or slopes, no motor vehicle shall be driven over, across, along, or within any shoulder or slope of any state controlled-access highway except at a location specifically authorized and posted by the department of transportation. The foregoing limitation shall not prevent tow trucks from using shoulders or slopes in as limited and incidental a manner as practicable when dispatched to the scene of an accident by a law enforcement agency or an authority, department or agency having jurisdiction over such controlled-access highway and all lanes are obstructed by traffic, provided, however, that the foregoing shall not relieve the driver of a tow truck from the duty to drive with due regard for the safety of all persons nor shall such provision protect the tow truck driver from the consequences of his or her reckless disregard for the safety of others and shall at all times operate such tow truck in compliance with all standards of care imposed to prevent those injuries or damages to persons or property of another which may result from the operator's negligence, recklessness or intentional misconduct, nor shall it prevent motor vehicles from using shoulders or slopes when directed by police officers or flagpersons, nor does it prevent motor vehicles from stopping, standing, or parking on shoulders or slopes where such stopping, standing, or parking is lawful.